The Trilobite of the Month closing 2016 is a beautifully preserved and prepped specimen of asteropygine trilobite out of Devonian Morocco, in the Order Phacopida. The genus is one of the large family Acastidae known for elaborately spined pygidia. Thanks to Frederik Lerouge for providing this image!

Images
like this help explain why trilobites are one of the best-known and appreciated groups of prehistoric animals. Each month, a new example of trilobite diversity will be showcased here. With over 20,000 described species, we may never exhaust the possibilities! If
you have a stunning image of a trilobite that you could share as a future "Trilobite of the Month," please let
me know!

THIS
SITE OPTIMIZED FOR VIEWING AT 1024 X 768 RESOLUTIONIn
these
pages, you may recognize species that are common, well-known, or sitting in a familiar museum collection! This guide might help you arrange trilobite diversity systematically, aid in identification of specimens, and enhance your understanding of these fascinating elements of Paleozoic biodiversity. Happy browsing! -- Sam Gon III

Trilobite
Order Fact Sheetsdetailed, descriptive characters and representative line drawings

Click
on any of the images above to be sent to a page featuring details on trilobites in that Order...

Trilobite
Order Galleriestrilobite images from various locations on the web, arranged by order

Agnostida

Redlichiida

Corynexochida

Odontopleurida

Lichida

Phacopida

Proetida

Asaphida

Harpetida

Ptychopariida

Click
on any of the images above to be sent to a gallery featuring photos of trilobites in that Order

SOURCES:The information in these pages was developed via examination and synthesis of the data present in a variety of works, including the two "Trilobite Treatises:" Moore
1959 (Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, including Trilobitomorpha) and Whittington
et al 1997 (Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, Trilobita, Revised, Volume 1: Introduction). Both may be reviewed
here. Other important sources are cited in specific pages of this site, and are also listed in a brief bibliography. Sources of photos and line drawings (where not original) are clearly cited. Other trilobite web sites and individuals were inspirational sources and are cited where relevant.The
three trilobite thumbnail images in the left column, for example, are c/o Andrew Milner. If you find your information or images on these pages without proper attribution, this is unintentional. Please contact
me to rectify the situation.

CAVEATS:Information about extinct animals is always subject to interpretation and differences of opinion. In particular, the higher
classification of arthropods and trilobites is neither
simple nor agreed upon by all trilobite workers. The summaries here are complicated by the fact that the 1997 revision of the Treatise only covers two orders in detail: Agnostida and Redlichiida. The others are in preparation, so my attempts to synthesize data on the other orders is likely to be incomplete, although the arrangement of the families and some characteristic descriptions were provided by Fortey (in Whittington et al 1997), and adjusted via recent articles (e.g., papers dealing with higher classification of the Asaphida, Proetida, Harpetida, Agnostida, and Lichida). Additional revisions continue to be suggested by various workers. Any errors in the information here should be attributed to the compiler, Sam
Gon III. Please inform him of any problems in accuracy or interpretation.

ABOUT
THE AUTHOR:This site's pages (and the majority of its figures) were designed and created by Dr. Sam
Gon III, a biologist (PhD, Animal Behavior; MA, Zoology (Ecology, Behavior and Evolution) who is greatly intrigued by the expression of ancientbiodiversity that trilobites represent. Sam's professional work is in the conservation of global biodiversity today. He serves as the Senior Scientist for The Nature Conservancy's Hawai‘i Field Office in Honolulu. Sam has long been interested in paleobiology, and in teaching himself about trilobites, using hyperlinks to cross-reference terminology and concepts, found himself developing a web resource of potential interest to a broader audience. The site was first unveiled in August 1999 and has attracted feedback from around the world, generating ongoing updates. For all the accolades this site has gathered, Sam is not a professional trilobitologist, but a devoted trilobitophile! In 2006 this culminated in his first paleontological publication, dealing withtrilobite
origins.

Listed as a reference at thein the category:Natural
History:
Reference Tools: Invertebrate Zoology

Recommended
as a web resource byThe American Museum of Natural History

Awarded by Scientific
AmericanOne of the top 50 science websites

Listed as a web resource onarthropod evolution at the:

Listed as a web resourcein biological sciences at:

One of the Ten Cool sitesin Natural History at the:

San Francisco

Featured as a trilobite web resource at:

a resource cited in

Awarded for Science Excellencein the category: Biology and EvolutionOn a Russian Paleontology Website:(“There has never been such a splendid site for Trilobites!!! EVERYTHING is there!!!! Such a pity....it’s in English.”) To
review other awards and accolades forA Guide to the Orders of Trilobitesplease
click hereFor your reading pleasure!

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